1. Field
The described technology relates generally to a rechargeable battery for improving uniformity of composite thickness on an edge of a coated unit.
2. Description of the Related Technology
A rechargeable battery can repeatedly perform charge and discharge, unlike a primary battery. A nickel-hydrogen battery, a lithium battery, and a lithium ion battery are each a type of rechargeable battery. A rechargeable battery can be manufactured in a pack form for use in a portable electronic device such as a mobile phone, a laptop computer, and a camcorder.
In one example, a rechargeable battery can include a jelly-roll type of electrode assembly having a positive electrode and a negative electrode on both sides of a separator; a case having the electrode assembly; a cap plate for closing and sealing an opening of a case; and an electrode terminal protruded out of the cap plate and electrically connected to an uncoated region of the electrode assembly through a lead tab.
In another example, a rechargeable battery can include, where the rechargeable battery is large, a plurality of coated units having predetermined width and length formed on an electrode plate providing an edge of an electrode plate from pressing, the electrode plate can be slit to manufacture a jelly-roll type or stack type of electrode assembly. In this instance, the edge of the electrode plate can be trimmed to be eliminated through scrapping.
A process for manufacturing rechargeable battery can be adapted where the edge of the electrode plate of the rechargeable battery is not used for the electrode assembly. In such a process, a composite slurry including a solvent in a composite including an active material, a conductive agent, and a binder can be coated on the electrode plate and air can be blown thereon to thereby form a composite thickness on the edge of the coated unit that can be thinner than a composite thickness in the center thereof.
The edges of the coated unit can form a composite inclined unit having a difference between the two composite thicknesses. The composite inclined unit can be laminated with an organic tape to be processed as a non-reversible region, such a step can increase the production cost of the rechargeable battery.
Further, in the case of a large rechargeable battery, the edge of the electrode plate cannot be scrapped by trimming when it is pressed. Therefore, the composite thickness on the edge of the coated unit becomes greater than the composite thickness in the center.
When the composite slurry is coated on the rear side of the electrode plate the composite inclined unit having the maximum composite thickness in the coated unit can be supported by a transfer roll of the coater. This process can generate wrinkles in the electrode plate whereby, a fault is generated on the electrode plate.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.